what is the best way to handle a "full" backup repository ?
In my case, my monthly backup target is full (NAS).
And so, the job fails since, if I understand well, it does its backup thing first and then remove older backups in the chain.

I removed some of the oldest backups files to get some space, but now, one of the VMs is not backupped anymore by the job (Error : file does not exist)

Please contact our support to solve the situation. The issue is that we keep track of our backup files and if some are lost (manual delete) we do not allow to continue to backup because something happened out of our control at the backup target.

There is a Repository-Advanced checkbox for "changeable media" which deactivate this monitoring and if the existing chain is not there anymore we will recreate the backups.

If you delete backups manually I strongly suggest to do this within our user interface.

yes, I already contacted the support team and the "problem" is solved. (very quickly as usual)
But, my question here = what is the best way to handle a "full" repository ?
You say : "do this within our user interface"
=> where can I manage that ?
when I go to "home / Backups" and then "right click" on the job name / properties, I can't see a way to remove some backup files there.

I can see this option, but it sounds like to me it would delete the entire job backup from the disk.
In my case, I only want to be able to delete some older backup (example : first full backup and all the next incremental backups in the chain. Or only some VMs's backups. But definitvely not the whole thing)

Suggestion : having a feature to "maximize" the number of backups => instead of telling Veeam B&R how many restore points we want to get. ("I" just want to store as much restore points as possible on the target media)

Your suggestion is good in theory but has several pitfalls, for example, the need to predict how much space will the next restore point occupy with the ability to free up the required space (currently retention is applied at the end of the job) and also the risk to lose all restore points in case the next one is too big.